This invention relates to railcar trucks and more particularly involves method and structure for assembling and disassembling friction shoes fitted and spring loaded within pockets such as the improved assembly of a truck bolster with friction shoes in the bolster pockets, and improved bolster and shoe components therefore.
A typical railcar truck comprises wheelsets mounted on two axles which support side frames at each side of the railcar and a transverse bolster extending between the side frames with the ends thereof supported between two vertical columns on load springs carried by each side frame. Usually a truck is located under each end of a railcar and the car itself is pivotally supported upon a centerplate centrally positioned on each bolster. Thus the weight of the railcar will cause the ends of the bolsters to move vertically on the load springs while confined between the vertical columns.
To provide proper damping for the suspension system, friction shoes are spring biased in pockets to frictionally retard vertical movement between the bolster and the side frame columns. Although it is possible to locate such pockets in the side frame columns, it is more common to locate the pockets in the bolster. The friction shoes have vertically disposed friction faces which contact friction plates secured to the opposite truck component. In certain types of such friction shoes there is a shoe slope surface, generally opposite the friction face, which declines from a top portion of the friction shoe to a bottom portion thereof and away from the friction face and which slope surface engages a sloped surface on the inside of the pocket. The latter type shoe also has a bottom opening or hole through which a control spring extends to the top portion of the shoe. The control spring urges the friction shoe against the pocket sloped surface and upwardly through the pocket, while the slope also guides the shoe outwardly of the pocket against the opposite truck member such as the friction plate on the frame vertical column.